Is there a link here to help calculate dosages in the small tanks or quarantine containers that are sometimes used for Bettas?

An example- Maroxy dosage calls for 2.5 per 10 gal. I learned a while ago to put whatever dose it is- powder or liquid- in 1 gal of treated water. That gallon is -in the maroxy case- 10x strength. Then replace 1/10th of the water in your quarantine vessel with that solution.

Now the trickier part. In some cases, betta tanks or quarantine vessels aren't filtered, so one would be changing water daily. I imagine at least 50-100%.

In Maroxy's case, it says to repeat daily up to 5 days. 100% water change would be easy- just put 10% more of the solution in your fresh water. 50% water change...? Do you treat 10% of the new water, or 10% of total?

Now to confuse things. Say a med says "leave in the tank for 48 hrs, do 25% water change and repeat dosage once". Ok, the first dose we've calculated above, done, but...

Um. really can't wait 48 hrs to change unfiltered water, or can you? So do you do 100% daily, putting initial dose back in new water.., and after 48 hrs, dilute by another 25%?

And I don't want to even start on maracide, where you treat on days 1,3,5 or Maracyn 2 where you use 2 pks on the first day, one pkt on days 2-5, lol. The first dose is always relatively easy, the rest get...

I know someone has figured this out somewhere, but can't find in in search..Thanks